EP0339306B1 - Lightsensitive composition with binders containing carboxyl groups - Google Patents

Description

The invention relates to a light-sensitive mixture with at least one addition-polymerizable, ethylenically unsaturated compound, a photoinitiator or a photoinitiator system and at least one polymeric binder which is a copolymer with in each case one or more different structural units A and B and at least one further structural unit containing carboxyl groups. Photosensitive mixtures are widely used in image recording materials, in particular in the production of photoresists, solder mask and printing plates.

Photopolymerizable resist materials are e.g. is known from US Pat. Nos. 3,469,982 and 3,547,730, which describe a film resist with a sandwich structure in the form of a photopolymerizable layer between a cover layer and a temporary support. This film resist can e.g. laminated to a copper backing, imagewise exposed, and developed to form a resist layer.

The resist layer produced in this way now allows selective etching, electroplating or soldering on the substrate. Particularly high demands are placed on photoresist films when they are used as a solder mask. The developed, photopolymerized layer must withstand temperatures up to 300 ° C. According to the prior art, such solder mask can be produced by spraying, pouring or printing liquid mixtures on a substrate or by laminating a dry film onto a substrate.

The photoresist films described usually consist of a temporary or permanent support, a photopolymerizable layer which contains a polymeric binder, addition-polymerizable compounds and a photoinitiator, and a cover layer. After the imagewise exposure has taken place, optionally after lamination to a substrate, the cover layer can be removed and the photopolymerized layer developed. Some photopolymerizable mixtures can be developed with organic solvents, some with aqueous solutions.

The polymeric binders of such photopolymerizable image recording materials, in particular those which can be developed in aqueous form, frequently contain acid functions, especially carboxyl functions. However, these groups are disadvantageous in many further processing steps. In the case of photoresists, e.g. in the case of alkaline etching or gold plating, the resist is removed, in the case of solder mask, lack of moisture and insulation properties.

Particularly completely aqueous processable photopolymer systems with high washout rates and possibly Due to their hydrophilic properties, fast stripping behavior shows weaknesses in other process steps, e.g. small development latitude, stripping with alkaline etching and with gold plating or insufficient climate resistance.

The modification of the carboxyl groups with melamine compounds to overcome the disadvantages mentioned is known in the field of photoresists (EP 01 15 354 and US 4,247,621). By adding the melamine compounds, however, the photosensitivity of the photopolymerizable mixtures can be reduced, so that such mixtures require longer exposure times. Furthermore, some of these compounds tend to crystallize when the photopolymerizable compositions are stored for a prolonged period, which then leads to the unusability of the recording materials produced therewith.

DE 33 29 443 discloses light-sensitive mixtures which contain binders with hydroxyl, alkoxy or acyloxy-substituted acid amide groups. Although a partial crosslinking of the binders can take place through a reaction of these oxygen-containing groups with hydroxyl or carboxy groups in the same or in a further binder, melamine compounds are also added to these photosensitive mixtures, especially when they are used in solder mask. However, these have the disadvantages already described.

It is therefore an object of the present invention to provide a photopolymerizable mixture based on binders containing carboxyl groups, the properties of which, after exposure and development, can be changed by a thermal aftertreatment in such a way that resists with improved chemical and physical properties, e.g. increased hydrolysis stability and greater mechanical resistance to etching systems, in gold plating or soldering. The general property profile should not be negatively influenced. Good storage stability, large processing and application range and exact reproduction of even the finest picture elements should be provided.

This object is achieved by a light-sensitive mixture, with at least one addition-polymerizable, ethylenically unsaturated compound, a photoinitiator or a photoinitiator system and at least one polymeric binder which is a copolymer with in each case one or more different structural units A and B and at least one further one containing carboxyl groups Structural unit is.

• I) 5 bis 50 Gew.% des Copolymeren von einer oder mehreren unterschiedlichen, carboxylgruppenhaltigen Struktureinheiten C1 und/oder C2 gebildet werden,
• II) der Anteil an einer oder mehreren unterschiedlichen Struktureinheiten A 5 bis 95 Gew.% beträgt,
• 111) der Anteil an einer oder mehreren unterschiedlichen Struktureinheiten B 0 bis 50 Gew.% beträgt,
• IV) A, B, C1 und C2 die Strukturen
  
  besitzen, worin
  • R₁ für H, CH₃, C₂H_s, Phenyl und Alkylphenyl,
  • R₂ für H, CH₃, Phenyl, -COORg, -CONR₁₀R₁₁ und -CN,
  • R₃, R₄, R₅ und R₆ für H und Alkyl und
  • R₇, R₈, Rg, R₁₀ und R¹¹ für H, Alkyl und Aryl, welche mit Hydroxy-, Ester-, Halogenid-, Keto-, Ether-und/oder Thioethergruppen substituiert sein können, stehen.

The invention is characterized in that

• I) 5 to 50% by weight of the copolymer are formed by one or more different structural units C1 and / or C2 containing carboxyl groups,
• II) the proportion of one or more different structural units A is 5 to 95% by weight,
• 111) the proportion of one or more different structural units B is 0 to 50% by weight,
• IV) A, B, C1 and C2 the structures
  
  own what
  • R _{1 is} H, CH ₃ , C ₂ H _s , phenyl and alkylphenyl,
  • R ₂ for H, CH ₃ , phenyl, -COORg, -CONR ₁₀ R ₁₁ and -CN,
  • R ₃ , R ₄ , R ₅ and R ₆ for H and alkyl and
  • R ₇ , R ₈ , Rg, R ₁₀ and R ^{11 represent} H, alkyl and aryl, which can be substituted by hydroxyl, ester, halide, keto, ether and / or thioether groups.

The light-sensitive mixture according to the invention contains polymeric binders, the structure of which can be changed after exposure and development. These binders include from structural units with adjacent carboxyl and amide groups which, after imagewise exposure and development of the photopolymerizable image recording materials, can be converted into the more hydrophobic imide groups by thermal post-treatment at 130 to 200 ° C. On the one hand, good developability is ensured due to the carboxyl groups present before the thermal treatment, and on the other hand, the conversion of these groups into imide groups by means of a thermal aftertreatment eliminates the disadvantageous properties of those carboxyl groups.

It was surprising that the use of the polymer binders mentioned in the mixture according to the invention can give those resists which have improved chemical and physical resistance to etching solutions, in gold plating and in soldering, without the properties of the recording material itself being influenced. For example, the photopolymerizable recording materials produced according to the invention include they have good storage stability at room temperature and are also stable at a laminator temperature of 120 ° C. This is all the more astonishing since the imide groups are formed by an insignificant increase in temperature during the subsequent thermal aftertreatment the thermal aftertreatment is not too long and the treatment time is not too long, since otherwise the entire photopolymerizable recording material becomes unusable.

From DE 25 12 693 it is known to use reaction products of styrene-maleic anhydride copolymers with dialkylamines as polymeric binders, so that copolymers with adjacent carboxyl and amide functions are formed, but since secondary amines are used, no binder is obtained whose Properties after exposure and development can be changed by a thermal aftertreatment. Furthermore, a maximum of 2/3 of the anhydride groups are reacted with amine in the cited document, since otherwise an excessive number of carboxyl groups would be introduced and thus a good adhesive bond of the light-sensitive layer on a metal substrate would be prevented during the heat coating. It was therefore not foreseeable for the person skilled in the art that the recording materials according to the invention, in which no dicarboxylic acid anhydride groups are present, can be laminated onto a substrate without difficulty.

EP 00 71 789 describes photopolymerizable resist layers which have improved adhesion to metallic substrate surfaces. This is achieved by introducing a certain percentage of amino functions. Since these can also be introduced, inter alia, by the reaction of binders containing maleic anhydride with aliphatic diamines, one also obtains neighboring carboxyl and amide functions, as required in the teaching according to the invention. However, diamines are not suitable as reaction components in the sense of the idea according to the invention, since they cause discoloration of the copper before the thermal aftertreatment, moreover cannot be introduced into the binders containing dicarboxylic acid anhydrides in a controlled manner, since crosslinking can occur, and also lead to residues during development lead, due to the better liability they cause.

DD 219 305 describes an alkaline developable, photopolymerizable mixture which, among other things, serves as a binder. may contain the reaction product of ammonia and a copolymer formed from an unsaturated hydrocarbon, a maleic anhydride-urea adduct and maleic anhydride. But like the diamines mentioned above, a binder containing urea also causes discoloration of the copper. In addition, according to the patent mentioned, these photopolymerizable mixtures are notable for good adhesion to polyester substrates. However, since an essential field of application of the light-sensitive mixture according to the invention is to be the production of layer transfer materials, binders containing urea adducts are not suitable for this.

Taking into account the prior art, the person skilled in the art could not therefore expect that resists produced with the light-sensitive mixture according to the invention have improved chemical and physical stability without the properties of the recording materials themselves being adversely affected.

• R₁ steht für H, CH₃, C₂Hs, Phenyl und Alkylphenyl, bevorzugt für H und CH₃
• R₂ für H, CH₃, Phenyl, -COORg, -CONR₁₀R₁₁ und -CN, bevorzugt für Phenyl, CO0R₉ und CONR₁₀R₁₁
• R₃, R₄, R₅ und R₆ für H und Alkyl und
• R₇, R₈, Rg, R10 und R11 für H, Alkyl und Aryl, welche mit Hydroxy-, Ester-, Halogenid-, Keto-, Ether-und/oder Thioethergruppen substituiert sein können, bevorzugt für unsubstituierte und hydroxysubstituierte Alkyl- und Arylgruppen.

The copolymers of the binder essential to the invention are each composed of one or more different structural units A and B and 5 to 50% by weight, preferably 10 to 30% by weight, of one or more different structural units C1 and / or C2 containing carboxyl groups.

• R ₁ represents H, CH ₃ , C ₂ Hs, phenyl and alkylphenyl, preferably H and CH ₃
• R ₂ for H, CH ₃ , phenyl, -COORg, -CONR ₁₀ R ₁₁ and -CN, preferably for phenyl, CO0R ₉ and CONR ₁₀ R ₁₁
• R ₃ , R ₄ , R ₅ and R ₆ for H and alkyl and
• R ₇ , R ₈ , Rg, R10 and R11 for H, alkyl and aryl, which can be substituted with hydroxyl, ester, halide, keto, ether and / or thioether groups, preferably for unsubstituted and hydroxy-substituted alkyl and Aryl groups.

The proportion of structural units A should be 5 to 95% by weight, preferably 10 to 90% by weight, and of structural units B should be 0 to 50% by weight, preferably 0 to 30% by weight.

The copolymers according to the invention can be obtained both by direct copolymerization of suitable monomers and by reaction of primary amines with copolymers which are formed by copolymerization of one or more ethylenically unsaturated dicarboxylic anhydrides with one or more comonomers. Suitable ethylenically unsaturated dicarboxylic anhydrides for the purposes of the invention are, for example, maleic anhydride, itaconic anhydride and citraconic anhydride. The proportion of the ethylenically unsaturated dicarboxylic anhydrides in the copolymers is 5 to 50% by weight, preferably 10 to 30% by weight.

Primary aliphatic or aromatic, optionally substituted, amines can be used as the amines according to the invention. The following functional groups are suitable as substituents for this: hydroxyl, ester, halide, keto, ether and / or thioether groups. Propylamine, butylamine, aminopropanol, 4-methoxyaniline, 4-aminophenol, decylamine and / or cyclohexylamine are preferably used.

Suitable comonomers which form the structural units A and B in the copolymer essential to the invention are unsaturated hydrocarbons, such as, for example, ethylene, propylene, substituted styrenes, butadiene and isoprene, and unsaturated carboxylic acids and their derivatives, such as (meth) acrylic acid, (meth) -Acrylic acid amides and (meth) acrylates. Methyl methacrylate, methyl acrylate, acrylamide, ethyl are preferred acrylate, butyl acrylate, styrene, isoprene and butadiene are used. The copolymers according to the invention should have molecular weights> 10,000, preferably from 30,000 to 80,000.

The proportion of the inventive copolymer containing adjacent carboxyl and amide groups in the total binder can be up to 100%. The amount of the total binder is generally 20 to 90% by weight, based on the total constituents of the mixture.

The following binders can e.g. can be used in combination with the binder essential to the invention: polyacrylates, polymethacrylates, polystyrene polymers and copolymers, polyurethanes, polyesters, polyamides. Preferred are: copolymers of methyl methacrylate, (meth) acrylic acid or maleic acid semiesters with styrene and copolymers of methacrylic acid and alkyl methacrylates.

Suitable addition-polymerizable, ethylenically unsaturated compounds which can be used alone or in combination with other monomers include tert-butyl acrylate, ethylene glycol diacrylate, 2-hydroxypropyl methacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate and methacrylate, polyoxyethylated trimethylol-1,4-propanol-1,4-propanol-1,4-propanol-1,4-diol Dihydroxybenzene dimethacrylate, decamethylene glycol diacrylate, styrene, diallyl fumarate, lauryl acrylate, methacrylamide or xylylene-bis-acrylamide.

The total amount of monomers in the photosensitive mixture is 10 to 80% by weight based on the total components of the mixture.

Practically all compounds known for this purpose can be used as photoinitiators or photoinitiator system in the light-sensitive mixture according to the invention, examples include: 9-phenylacridine, 9,10-dimethylbenz (a) phenazine, benzophenone / Michler's ketone, hexarylbisimidazole / mercaptobenzoxazole, benzil dimethyl ketal, Thioxanthones / amines. The photoinitiators are generally used in an amount of 0.01 to 10% by weight.

The light-sensitive mixture and the image-recording materials produced therefrom can also contain further additives, e.g. Contain dyes, pigments, plasticizers, adhesion promoters, fillers and / or stabilizers.

A mixture according to the invention is preferred in the form of a light-sensitive layer which is located on a support, i.e. in the form of an image recording material. Suitable layer supports are, for example, paper, metallic supports, metal-coated supports, glass, ceramic supports or plastic films, e.g. made of polyethylene, polycarbonate, polyamide or polyester. The light-sensitive mixture is applied to the layer support, for example, by spraying, dipping or pouring from a solution. The layer thickness is usually 5 to 200 µm.

In particular, the light-sensitive mixture according to the invention is used for the production of resist materials, especially as layer transfer materials. For this purpose, the light-sensitive mixture is applied to a temporary layer support, preferably a polyester film, and a removable plastic film is laminated on as a cover film. The cover film is then removed to produce the resist image, and the light-sensitive layer is laminated onto a permanent support, usually a copper surface. The material is then exposed and developed imagewise, and the temporary layer support can be removed before or after the exposure. Development takes place by washing out the unpolymerized image parts with suitable solutions, such as aqueous-alkaline solutions, organic solvents or mixtures or corresponding aqueous solutions, which may also contain surface-active substances.

After the development process, the material is then subjected to a thermal aftertreatment. This can be done by heating the material in an electric oven, drying cabinet or using an IR lamp. The temperature and the heating time depend on the composition of the resist materials used. In general, the materials are heated to 120 to 200 ° C for 10 to 60 minutes.

The resist layer produced in this way can then be further processed in the usual way, using the known electroplating, etching or soldering methods, without the resist being detached or underplating occurring. The photopolymerized layer remaining on the support can easily be completely removed if necessary by treatment with a conventional decoating solution. For this, e.g. strongly alkaline, aqueous solutions, which are usually used at elevated temperatures between 30 and 90 ° C in continuous machines or tanks or organic solvents such as e.g. Methylene chloride.

Although the invention has preferably been described in the above description in its application as a layer transfer material for photoresists, it is not restricted to this application. It can be used in all cases in which it is important to produce pictorial stencils or relief materials of particularly high chemical and physical resistance.

The following examples are intended to explain the invention.

example 1 A) Preparation of the copolymer containing amide and carboxyl groups

20 g of a copolymer of methyl methacrylate / styrene / maleic anhydride (SZ = 115 = ̂ 20.43 mmol maleic acid / 20 g polymer) were dissolved in 100 ml methylene chloride at room temperature. 1.3 g (= ̂ 22.47 mmol) of propylamine in 100 ml of methylene chloride were added to the polymer solution. Warming to 25 ° C occurred. After stirring for 4 hours at room temperature, the polymer was precipitated by pouring the solution into 1 liter of petroleum ether (40-60 ° C.), filtered off and dried in vacuo. The IR spectrum no longer showed carbonyl vibrations at 1860 cm ^-1 and 1780 cm ^-1 .

B) Production of a dry resist film

Die Gießlösung wurde auf eine 25 um dicke Polyesterfolie aufgebracht, so daß eine Trockenschichtdicke von 42 g/m² erzielt wurde.The following casting solution was prepared:

The casting solution was applied to a 25 μm thick polyester film, so that a dry layer thickness of 42 g / m ^{2 was} achieved.

C) Use of the dry resist film produced under B)

The dry resist film produced under B) was laminated under standard conditions onto base material clad with 35 μm copper plating at 110 ° C. roller temperature at 2.0 m / min, exposed through a plating template at 50 mj / cm ² and with 1% Na ₂ CO ₃ - Solution developed at 30 ° C in a continuous processor. The clarification time was 25 seconds. A plate developed in this way was treated in a commercially available MRC gold bath at a current of 1A / dm ² without thermal treatment. Already after 6 minutes, corresponding to an electroplating <2 μm gold, a peeling off of the resist and strong underplating were observed. However, if a plate developed as above was thermally treated at 150 ° C. for 5 minutes, then an electroplating application> 6 μm gold was achieved after 18 minutes without the resist being detached or underplating occurring.

Both plates could then be stripped perfectly and cleanly in 3% KOH at 50 ° C:

Example 2 A) Preparation of the polymer

20 g (= ̂ 20.43 mmol maleic acid) of the copolymer from Example 1A were dissolved in 300 ml of methylene chloride at room temperature. 1.53 g (= ̂ 20.4 mmol) of 1-amino-2-propanol were dissolved in 50 ml of methylene chloride and added dropwise to the polymer solution with stirring. Warming to 27 ° C occurred. After a reaction time of 4 hours, the polymer was precipitated by pouring it into 2.5 l of petroleum ether (40-60 ° C.), filtered off and dried in vacuo. No carbonyl vibrations at 1860 cm ^-1 and 1780 cm ^-1 were found in the IR spectrum.

B) Production of a dry resist film

Die Herstellung des Trockenresistfilms erfolgte wie in Beispiel 1 B.The following casting solution was prepared:

The dry resist film was produced as in Example 1 B.

C) Use of the dry resist film produced under B)

The dry resist film was laminated, exposed and developed on a copper-clad base material as in Example 1C. A plate developed in this way was treated without thermal treatment in the gold bath described in Example 1C. Detachment of the resist was observed after only 5 minutes (corresponding to <2 μm gold application).

On the other hand, after a thermal treatment of 10 minutes at 150 ° C.,> 8 μm gold could be deposited after 22 minutes without the resist being detached or underplating occurring.

Both plates could then be stripped perfectly and cleanly in 3% KOH at 50 ° C:

Example 3 A) Preparation of the polymer

100 g (= ̂ 0.102 mol of maleic acid) of the copolymer from Example 1A were dissolved in 500 ml of tetrahydrofuran at room temperature. 12 g (= ̂ 0.11 mol) of p-aminophenol were dissolved in 100 ml of tetrahydrofuran and added to the polymer solution. The mixture was heated to 40 ° C. and stirred at this temperature for 4 h. The polymer was precipitated by pouring the solution into 3 l of petroleum ether (40-60 ° C.), filtered off and dried in vacuo. No carbonyl vibrations at 1860 cm ^-1 and 1780 cm ^-1 were found in the IR spectrum.

B) Production of the dry resist film

Der Trockenresistfilm wurde wie in Beispiel 1 B hergestellt.The following casting solution was prepared:

The dry resist film was made as in Example 1B.

C) Compounds of the dry resist film produced under B)

The dry resist film was processed as in Example 1C. A plate developed in this way was treated without thermal treatment in the gold bath described in Example 1C. Detachment of the resist was observed after only 6 minutes (corresponding to <2 μm gold application). After a thermal treatment of 10 minutes at 150 ° C.,> 6 μm gold was deposited after 18 minutes without the resist being detached or undergoing electroplating. Both plates could be stripped perfectly and cleanly in 3% KOH solution at 50 ° C:

Example 4

The following casting solution was prepared: In

Aus dieser Gießlösung wurde wie in Beispiel 1 ein Trockenresistfilm mit 42 g/m² Auftragsmasse hergestellt. Der Trockenresistfilm wurde wie in Beispiel 1C laminiert, mit 50 mj/cm² belichtet und in 1%iger Na₂C0₃-Lösung bei 30° C entwickelt. Die Klärzeit betrug 20 sec.1.64 g of isopropanolamine were added and the mixture was stirred for 1 hour. The following was further added to this solution:

A dry resist film with an application weight of 42 g / m ^{2 was} produced from this casting solution as in Example 1. The dry resist film was laminated as in Example 1C, exposed to 50 mj / cm ² and developed in 1% Na ₂ CO ₃ solution at 30 ° C. The clarification time was 20 sec.

A plate developed in this way was subjected to the thermal treatment described in Example 1C Gold bath treated. Detachment of the resist was observed after only 6 minutes (corresponding to <2 μm gold application). After a thermal treatment of 10 minutes at 150 ° C.,> 7 μm gold was deposited after 20 minutes without the resist being detached or underplating occurring.

Both plates could be stripped perfectly and cleanly in 3% KOH solution at 55 ° C:

Example 5

Diese Lösung wurde 1 h gerührt. Anschließend wurde weiter zugegeben:

Die Gießlösung wurde auf eine 25 um dicke Polyesterunterlage mit einer Trockenschichtdicke von 42 g/m² aufgebracht.The following casting solution was prepared:

This solution was stirred for 1 hour. The following was then added:

The casting solution was applied to a 25 μm thick polyester base with a dry layer thickness of 42 g / m ² .

The dry resist film was laminated under normal conditions to base material clad with 35 μm copper at 110 ° C. roller temperature at 2.0 m / min, exposed to 60 mj / cm ² through a galvanic template and developed in a commercial processor with 1,1,1-trichloroethane .

The dry resist film was processed as in Example 1C. A plate developed in this way was treated without thermal treatment in the gold bath described in Example 1C. Detachment of the resist was observed after only 8 minutes (corresponding to <3 μm gold application). After a thermal treatment of 10 minutes at 150 ° C.,> 8 μm gold was deposited after 22 minutes without the resist being detached or undergoing electroplating.

Both plates could be stripped perfectly and cleanly in methylene chloride / methanol (95/5).

Example 6

The following casting solutions were produced:

The casting solutions were applied to a 25 μm thick polyester film, so that a dry layer thickness of 50 μm was achieved.

The dry resist films A and B were laminated to a COMB conductor pattern according to IPC-SM 840A, which had previously been sprayed with tripropylene glycol diacrylate.

Both plates were exposed to 80 mj / cm ² through the corresponding test template and developed with a 1% Na ₂ CO ₃ solution at 30 ° C.

After development, both plates were each treated 1 at 150 ° C. and then exposed to 4 J / cm ² . The moisture and insulation properties were measured in accordance with the IPC Class III test conditions. The following resistances were measured:

Claims (10)

1. A lightsensitive composition comprising

a) at least one addition-polymerizable, ethylenically unsaturated compound,

b) a photoinitiator or a photoinitiator system and

c) at least one copolymeric binder containing one or more structural units A and B and at least one additional structural unit containing carboxyl groups,
characterized in that

I) 5 to 50 percent by weight of the copolymer is formed from one or more different structural units C1, C2 or combinations thereof containing carboxyl groups,

II) the proportion of one or more different structural units A is 5 to 95 percent by weight,

III) the proportion of one or more different structural units B is 0 to 50 percent by weight and

IV) A, B, C1 and C2 have the structures

in which

R₁ = H, CH₃, C₂H_s, phenyl and alkylphenyl

R₂ = H, CH₃, phenyl, -COOR₉, -CONR₁₀R₁₁ and -CN,

R₃, R₄, Rs, and R₆ = H and alkyl and

R₇, R₈, Rg, R₁₀ and R₁₁ = H, alkyl and aryl, which is unsubstituted or substituted with hydroxy, ester, halogen, keto, ether or thioether groups.

2. A lightsensitive composition according to claim 1 characterized in that the specified copolymer is present as the only binder.

3. A lightsensitive composition according to claim 1 or 2 characterized in that the specified copolymer is the reaction product of a copolymer formed from one or more ethylenically unsaturated dicarboxylic acid anhydrides and one or more ethylenically unsaturated compounds with primary amine.

4. A lightsensitive composition according to claim 3 characterized in that maleic acid anhydride, itaconic acid anhydride or citraconic acid anhydride is used as an ethylenically unsaturated dicarboxylic acid anhydride.

5. A lightsensitive composition according to claim 3 or 4 characterized in that unsubstituted or hydroxy substituted alkyl or aryl amine is used.

6. A lightsensitive composition according to claims 3 to 5 characterized in that styrene, isoprene, butadiene, (meth)acrylic acid, (meth)acrylamides or (meth)acrylates are used as comonomers.

7. A lightsensitive composition according to claims 1 to 6 characterized in that it is used in the form of a solid, transferable layer on a support of synthetic resin film and optionally one or more cover sheets are used.

8. A lightsensitive composition according to claims 1 to 7 characterized in that it is used in the form of a solid layer on a metallic support or a metal-clad support.

9. Use of the lightsensitive composition according to claims 1 to 8 in layer transfer materials for the production of photoresist layers and solder masks.

10. Use of the lightsensitive composition according to claims 1 to 8 in an image recording process comprising imagewise exposure of a layer consisting of a photopolymerizable composition according to the invention, following development by washing-off of the unexposed areas, and thermal posttreatment at 130 ° C to 200 C.